Polioencephalomalacia

We are once again seeing several cases of P.E. (polio encephalomalacia), a nervous disease seen primarily in calves and younger stock. P.E. is caused by a lack of vitamin B1 (not to be confused with a cobalt deficiency, which is associated with a vitamin B12 deficiency). P.E is thought to be nutritionally induced, when there is a sudden change in diet from stalky, higher DM diet, to a lush, low fibre diet. A high dietary sulphur intake, especially with brassicas, has also been incriminated as a cause of P.E.

Calves with P.E. appear blind, may walk aimlessly, appear wobbly, have muscle tremors and head press. If calves are treated early in the disease process with a series of vitamin B1 injections, survival rates are good. In an outbreak situation we have had good success, by prophylactically treating the remaining, unaffected calves, in the group with an oral vitamin B1 drench. This has proved a very cost effective preventative measure.

Pink Eye Update

Whilst Pinkeye can be tricky to see, it can certainly become an eyesore if left to brew away! Pink eye is caused by bacteria (Moraxella bovis). It becomes a pesky problem heading into the summer months as wind, heat, dust, flies and long grass can weaken the natural defences of the eye and cause an infection.

Pink eye is incredibly contagious and can rapidly move through a mob, so it pays to get on top of it quickly. Signs of pink eye begin with weepy, clear discharge and squinting which then can progress to discoloured/white eyes which can develop deep ulcers. If left untreated, it is very painful and uncomfortable. It can lead to nasty ulcers, blindness and reduced growth rates, as well as it being a significant welfare issue. Lesions quickly worsen for an animal and eye damage can be irreversible (partial or complete blindness).

Treatment of pink eye is either with Orbenin eye ointment OR injectable tetracyclines (Engemycin or Bivatop). If you are having particularly bad problems this year, or it is becoming an annual problem, then come talk to us to see what management factors may be of help. A single dose of Piliguard vaccine given 3-6 weeks before the risk period will significantly reduce the risk of an outbreak.

Calf Weaning

Making sure a calf is fully prepared before weaning reduces the chance that they will need preferential treatment post-weaning. Preferentially managing small groups of animals to ‘catch them up’ is time consuming and can be difficult to manage, so it is best avoided by good management early on.

Factors to consider before weaning calves:

1) Rumen Development – Are they consuming the desired amount of feed? Is its rumen sufficiently developed to be weaned off milk?

• The only way this can be assessed is by measuring the amount of concentrate or pasture they are readily eating, which should be at least 1kg/day of meal or 2kg/day of pasture.

2) Weight – Individual calves should reach a minimum weight prior to weaning.

• No specific weaning weight has been defined by research, however common weights used are 70kg for Jerseys, 80kg for Crossbreds, and 90kg for Friesians.

• Reaching a minimum weight is an important milestone as it indicates that they are ready to transition from individual to group management.

3) Age – A combination of weight and age is often good to use when making the weaning decision eg. a minimum of 8 weeks AND 90kg.

4) Ability to Compete Within a Group – Is the calf able to compete within the group before they are weaned? Any that aren’t should be held back until they are.

The aim is to have calves that continue to gain weight post-weaning - they should never lose weight or remain static. Some animals don’t thrive post-weaning so it is a good idea to weigh them 7-10 days post-weaning to make sure they have gained weight. Any that haven’t may need continued access to calf meal, regardless of weight or age, or examination by a vet.

Relocating Calves

Relocating calves can result in growth checks, or be a trigger for other animal health issues including pneumonia, scouring and parasites. Recently weaned calves are at particular risk as they are also undergoing changes in diet, rumen development and are usually younger in age.

A few criteria to consider for relocating recently weaned calves include:

• Fully weaned and off milk for at least two weeks.

• Meet the minimum target weight for their age.

• Transitioned onto a full pasture diet or supplement provided for transition.

• Competing and coping well within the group.

• Drenched and vaccinated.

• In good health.

Minimising Coccidiosis Outbreaks

Coccidiosis is a parasitic disease which primarily occurs in young cattle between 3-8 months of age. Occasionally the disease is seen in animals as young as 4 weeks. Coccidia are widespread in the environment, however disease only occurs if large numbers of the parasite are ingested or if their resistance is lowered due to stress, poor nutrition, concurrent disease, or heavy worm burdens. Coccidia can survive for long periods on pasture - grazing calves on the same paddocks each year increases the risk due to significant build-up of oocysts on paddocks, especially in wet conditions.

Calves present with diarrhoea typically containing mucous and blood. They frequently strain to pass faeces, swish their tails, are often off their food and appear uncomfortable and unhappy. Faecal staining on the back of the thighs is often evident. Affected calves lose weight rapidly due to gut damage and growth rates can suffer for months after the disease. Most calf meals contain a coccidiostat which prevents the infection becoming established – however the protective effect relies on calves consuming about 1kg of meal/day. Often mobs are eating more than this on average but there are always some calves that eat less than others.

Treatment is with Toltrox (as a single oral dose) or injectable Amphoprim (antibiotic) and are usually effective, especially when instigated early in the disease. History and clinical signs are often enough for a presumptive diagnosis, however faecal samples are required to confirm and are relatively quick and cheap to perform.

Turbo Initial is also a good product to keep in mind – a dual action double combination drench (Eprinomectin and Levamisole) with added Diclazural for coccidia control. Post-weaning off calf meal, some calves will become very susceptible to coccidiosis. Calves at risk can be strategically treated with Turbo Initial once at 18-20 days after weaning off meal. This allows them time to establish an infection and gain some immunity, then treating the infection before it can cause disease.

Calf Scours in the Latter Half of Calving

We field a lot more calls about calf scours in late August and September than we do in the earlier stages of calving. When we visit calf rearing facilities that are having problems at this later stage, one of the notable issues is the accumulated deposition of infectious scours in pens. In the case of Rotavirus, it is possible to infect 10,000 calves from just 1 gram of faeces! So, when a calf pen become thick with scour, the sheer volume of viral (and bacterial) load may be enough to overwhelm good colostrum antibody immunity in what are otherwise healthy calves.

It doesn’t matter how much disinfectant is sprayed around a very heavily contaminated pen, the reality is you cannot sterilise it. Placing new calves in a heavily contaminated pen will always have a negative outcome.

Where possible avoid housing new or young calves in heavily contaminated pens. Either completely clean them out (disinfect and replace bedding) or get them outside. Straw bale outside shelters may need to be moved frequently so calves do not camp for extended periods in poo. Scours vaccines do work, but they work best when the whole herd has been vaccinated which ensures the calf pens stay cleaner for longer (partial herd or just doing late calvers is a compromise).

Remember to use Metacam to speed recovery and appetite, supply free access Optiguard as a gut protectant, and use Vet Centre Rehydrate electrolytes (we believe our formulation is the best on the market). Discuss whether antibiotic use is appropriate with your vet.

Finally ensure your hay/racks are placed high and are full to dissuade calves eating contaminated sawdust or wood chips on the ground and getting infected. Calves which are sick should never be place on OAD feeds.

Rehydrate – Calf Electrolyte

Rehydrate is an electrolyte mix that our practice formulated. Its ingredient list is far superior to that offered by many other commercial preparations but at a fraction of the cost.

• It has great palatability

• It corrects metabolic acidosis in dehydrated calves

• The formulation ensures speedier absorption of fluid fraction of solution